diff -r 000000000000 -r 6474c204b198 dom/time/TimeChangeObserver.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dom/time/TimeChangeObserver.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,179 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "TimeChangeObserver.h"
+#include "mozilla/Hal.h"
+#include "mozilla/Observer.h"
+#include "mozilla/HalTypes.h"
+#include "nsWeakPtr.h"
+#include "nsTObserverArray.h"
+#include "mozilla/ClearOnShutdown.h"
+#include "mozilla/Services.h"
+#include "mozilla/StaticPtr.h"
+#include "nsPIDOMWindow.h"
+#include "nsContentUtils.h"
+#include "nsIObserverService.h"
+#include "nsIDocument.h"
+
+using namespace mozilla;
+using namespace mozilla::hal;
+using namespace mozilla::services;
+
+class nsSystemTimeChangeObserver : public SystemClockChangeObserver,
+                                   public SystemTimezoneChangeObserver
+{
+  typedef nsTObserverArray<nsWeakPtr> ListenerArray;
+public:
+  static nsSystemTimeChangeObserver* GetInstance();
+  virtual ~nsSystemTimeChangeObserver();
+
+  // Implementing hal::SystemClockChangeObserver::Notify()
+  void Notify(const int64_t& aClockDeltaMS);
+
+  // Implementing hal::SystemTimezoneChangeObserver::Notify()
+  void Notify(
+    const mozilla::hal::SystemTimezoneChangeInformation& aSystemTimezoneChangeInfo);
+
+  nsresult AddWindowListenerImpl(nsPIDOMWindow* aWindow);
+  nsresult RemoveWindowListenerImpl(nsPIDOMWindow* aWindow);
+
+private:
+  nsSystemTimeChangeObserver() { };
+  ListenerArray mWindowListeners;
+  void FireMozTimeChangeEvent();
+};
+
+StaticAutoPtr<nsSystemTimeChangeObserver> sObserver;
+
+nsSystemTimeChangeObserver* nsSystemTimeChangeObserver::GetInstance()
+{
+  if (!sObserver) {
+    sObserver = new nsSystemTimeChangeObserver();
+    ClearOnShutdown(&sObserver);
+  }
+  return sObserver;
+}
+
+nsSystemTimeChangeObserver::~nsSystemTimeChangeObserver()
+{
+  UnregisterSystemClockChangeObserver(this);
+  UnregisterSystemTimezoneChangeObserver(this);
+}
+
+void
+nsSystemTimeChangeObserver::FireMozTimeChangeEvent()
+{
+  ListenerArray::ForwardIterator iter(mWindowListeners);
+  while (iter.HasMore()) {
+    nsWeakPtr weakWindow = iter.GetNext();
+    nsCOMPtr<nsPIDOMWindow> innerWindow = do_QueryReferent(weakWindow);
+    nsCOMPtr<nsPIDOMWindow> outerWindow;
+    nsCOMPtr<nsIDocument> document;
+    if (!innerWindow ||
+        !(document = innerWindow->GetExtantDoc()) ||
+        !(outerWindow = innerWindow->GetOuterWindow())) {
+      mWindowListeners.RemoveElement(weakWindow);
+      continue;
+    }
+
+    nsContentUtils::DispatchTrustedEvent(document, outerWindow,
+      NS_LITERAL_STRING("moztimechange"), /* bubbles = */ true,
+      /* canceable = */ false);
+  }
+}
+
+void
+nsSystemTimeChangeObserver::Notify(const int64_t& aClockDeltaMS)
+{
+  // Notify observers that the system clock has been adjusted.
+  nsCOMPtr<nsIObserverService> observerService = GetObserverService();
+  if (observerService) {
+    nsString dataStr;
+    dataStr.AppendFloat(static_cast<double>(aClockDeltaMS));
+    observerService->NotifyObservers(
+      nullptr, "system-clock-change", dataStr.get());
+  }
+
+  FireMozTimeChangeEvent();
+}
+
+void
+nsSystemTimeChangeObserver::Notify(
+  const SystemTimezoneChangeInformation& aSystemTimezoneChangeInfo)
+{
+  FireMozTimeChangeEvent();
+}
+
+nsresult
+mozilla::time::AddWindowListener(nsPIDOMWindow* aWindow)
+{
+  return nsSystemTimeChangeObserver::GetInstance()->AddWindowListenerImpl(aWindow);
+}
+
+nsresult
+nsSystemTimeChangeObserver::AddWindowListenerImpl(nsPIDOMWindow* aWindow)
+{
+  if (!aWindow) {
+    return NS_ERROR_ILLEGAL_VALUE;
+  }
+
+  if (aWindow->IsOuterWindow()) {
+    aWindow = aWindow->GetCurrentInnerWindow();
+    if (!aWindow) {
+      return NS_ERROR_FAILURE;
+    }
+  }
+
+  nsWeakPtr windowWeakRef = do_GetWeakReference(aWindow);
+  NS_ASSERTION(windowWeakRef, "nsIDOMWindow implementations shuld support weak ref");
+
+  if (mWindowListeners.IndexOf(windowWeakRef) !=
+      ListenerArray::array_type::NoIndex) {
+    return NS_OK;
+  }
+
+  if (mWindowListeners.IsEmpty()) {
+    RegisterSystemClockChangeObserver(sObserver);
+    RegisterSystemTimezoneChangeObserver(sObserver);
+  }
+
+  mWindowListeners.AppendElement(windowWeakRef);
+  return NS_OK;
+}
+
+nsresult
+mozilla::time::RemoveWindowListener(nsPIDOMWindow* aWindow)
+{
+  if (!sObserver) {
+    return NS_OK;
+  }
+
+  return nsSystemTimeChangeObserver::GetInstance()->RemoveWindowListenerImpl(aWindow);
+}
+
+nsresult
+nsSystemTimeChangeObserver::RemoveWindowListenerImpl(nsPIDOMWindow* aWindow)
+{
+  if (!aWindow) {
+    return NS_OK;
+  }
+
+  if (aWindow->IsOuterWindow()) {
+    aWindow = aWindow->GetCurrentInnerWindow();
+    if (!aWindow) {
+      return NS_ERROR_FAILURE;
+    }
+  }
+
+  nsWeakPtr windowWeakRef = do_GetWeakReference(aWindow);
+  mWindowListeners.RemoveElement(windowWeakRef);
+
+  if (mWindowListeners.IsEmpty()) {
+    UnregisterSystemClockChangeObserver(sObserver);
+    UnregisterSystemTimezoneChangeObserver(sObserver);
+  }
+
+  return NS_OK;
+}